Wireless terminal, access point, system provided with the same, and wireless communication method

Abstract

A wireless LAN communications system with high transmission efficiency is provided. When a first wireless terminal normally receives a Data1 signal from an access point, the wireless terminal transmits an ACK signal. In the case where the wireless terminal has transmission data, the client transmits a Data2 signal to the access point after an SIFS interval. Meanwhile, when the access point or a second wireless terminal receives the ACK signal from the first wireless terminal, the second client waits a (DIFS+random number) interval, in accordance with the IEEE 802.11 standard. As a result, the first wireless terminal is able to transmit the Data2 signal with priority, without interference from signals from other devices.

1. A wireless terminal for wirelessly communicating with an access point via a wireless LAN (Local Area Network), the wireless terminal comprising:
 a transmission unit which transmits a wireless signal; 
 a receiving unit which receives a wireless signal; and 
 a communication control unit; 
 wherein, when the receiving unit receives the wireless signal addressed to the terminal itself from the access point, if transmission data is present, in priority to transmission of wireless signals from other wireless terminals connected to the access point, the communication control unit causes the wireless signal including the transmission data to be transmitted from the transmission unit; 
 wherein after the receiving unit receives the wireless signal addressed to the terminal itself from the access point and the communication control unit causes an ACK signal, notifying the access point that the wireless signal was normally received, to be transmitted from the transmission unit, if the wireless signal is not received during the DIFS (Distributed Coordination Function Inter Frame Space) interval and also where transmission data is present, the communication control unit, after the DIFS interval has passed, causes the wireless signal including the transmission data to be transmitted from the transmission unit; and 
 wherein, when the receiving unit receives an ACK signal transmitted by another wireless terminal, if the wireless signal is not received during the (DIFS+random number+α(α>0)) interval and also transmission data is present, the communication control unit, after the (DIFS+random number+α) interval has passed, causes the wireless signal including the transmission data to be transmitted from the transmission unit. 
 
     
     
       2. A wireless terminal for wirelessly communicating with an access point via a wireless LAN (Local Area Network), the wireless terminal comprising:
 a transmission unit which transmits a wireless signal; 
 a receiving unit which receives a wireless signal; and 
 a communication control unit; 
 wherein, when the receiving unit receives the wireless signal addressed to the terminal itself from the access point, if transmission data is present, in priority to transmission of wireless signals from other wireless terminals connected to the access point, the communication control unit causes the wireless signal including the transmission data to be transmitted from the transmission unit; 
 wherein, after the receiving unit receives the wireless signal addressed to the terminal itself from the access point and the communication control unit causes an ACK signal, notifying the access point that the wireless signal was normally received, to be transmitted from the transmission unit, if the wireless signal is not received during the PIFS (Point Coordination Function Inter Frame Space) interval and also where transmission data is present, the communication control unit, after the PIFS interval has passed, causes the wireless signal including the transmission data to be transmitted from the transmission unit; and 
 wherein, when the receiving unit receives an ACK signal transmitted by another wireless terminal, if the wireless signal is not received during the (DIFS+random number) interval and also transmission data is present, the communication control unit, after the (DIFS+random number) has passed, causes the wireless signal including the transmission data to be transmitted from the transmission unit.